Easily Separable Racemic and Meso Isomers of a Salen-Based Cryptophane for Selective Guest Binding

A salen-based cryptophane cage was synthesized via dynamic covalent imine chemistry, affording separable meso and racemic isomers. Single-crystal X-ray analysis confirmed the structure of the racemic form. The isomers exhibited slow interconversion in solution, enabling an individual study of their properties. The racemic isomer bound quaternary ammonium guests with notable size selectivity, highlighting the potential of imine-based cryptophanes as functional hosts for molecular recognition.